CVE-2016-1920 in KNOX
Summary
by MITRE
Samsung KNOX 1.0.0 uses the shared certificate on Android, which allows local users to conduct man-in-the-middle attacks as demonstrated by installing a certificate and running a VPN service.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/15/2026
The vulnerability described in CVE-2016-1920 represents a critical security flaw within Samsung KNOX 1.0.0, a mobile security platform designed to protect enterprise devices running on Android operating systems. This weakness stems from the improper handling of cryptographic certificates within the platform's architecture, specifically utilizing a shared certificate across multiple security functions. The shared certificate mechanism creates a fundamental security risk that undermines the integrity of the entire security framework. The vulnerability is particularly concerning because it affects the core trust mechanisms that KNOX relies upon to establish secure communications and maintain device integrity. When a shared certificate is used across different security contexts, it creates a single point of failure that malicious actors can exploit to compromise the entire security infrastructure. The certificate in question is not only used for authenticating the KNOX platform itself but also for establishing secure communication channels and verifying the authenticity of security services. This design flaw allows local users to leverage the shared certificate for unauthorized activities that would normally be restricted. The vulnerability directly enables man-in-the-middle attacks by providing attackers with the means to install their own certificates and subsequently operate malicious VPN services that can intercept and manipulate communications between the device and external networks. This attack vector is particularly dangerous because it operates at the local user level, meaning that any individual with access to the device can exploit this weakness without requiring external network access or sophisticated attack infrastructure.
The technical implementation of this vulnerability demonstrates poor security design principles that violate fundamental concepts of certificate management and trust isolation. The use of a single shared certificate across multiple security domains creates a scenario where compromising one security function automatically compromises all functions that rely on that certificate. This approach violates the principle of least privilege and separation of concerns that are essential for maintaining robust security boundaries. The shared certificate mechanism essentially eliminates the cryptographic isolation that should exist between different security components, allowing attackers to escalate their privileges and access functions that should remain protected. From a cybersecurity perspective, this vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in certificate handling, and specifically relates to improper certificate validation and certificate reuse. The vulnerability also maps to ATT&CK technique T1552.001, which covers "Unsecured Credentials" and demonstrates how attackers can exploit weak certificate management to gain unauthorized access to secure communications. The attack chain begins with local privilege escalation through certificate installation, followed by the establishment of malicious VPN services that can intercept and modify network traffic. This creates a persistent threat vector that can be maintained even after the initial compromise, as the installed certificate remains valid and trusted by the system.
The operational impact of this vulnerability extends beyond simple man-in-the-middle attacks to encompass a broader range of security compromises that can affect enterprise environments. Organizations relying on Samsung KNOX for mobile device security face significant risks when this vulnerability exists, as attackers can potentially access sensitive corporate data, intercept communications, and perform unauthorized transactions. The vulnerability affects the confidentiality, integrity, and availability of enterprise communications, as the shared certificate can be used to decrypt sensitive information, modify data in transit, and disrupt normal network operations. Mobile device management systems that depend on KNOX for security enforcement become compromised, potentially allowing attackers to bypass security policies and access protected resources. The vulnerability also impacts the trust relationships that enterprises establish with their mobile device security infrastructure, as the compromised certificate can be used to impersonate legitimate security services. This creates a cascading effect where multiple security controls become ineffective, as the root cause lies in the certificate management system itself rather than in individual security components. The persistence of this vulnerability means that once exploited, the compromise can remain undetected for extended periods, allowing attackers to maintain access and continue their activities without detection. Enterprise networks that depend on secure mobile communications become vulnerable to data exfiltration, insider threats, and external attacks that leverage this weakness.
Mitigation strategies for CVE-2016-1920 require immediate attention and involve both immediate remediation steps and long-term architectural improvements. Organizations should immediately implement certificate revocation procedures for the affected shared certificate and deploy updated KNOX versions that address the certificate management flaw. The implementation of proper certificate lifecycle management practices is essential, including the use of unique certificates for different security functions and regular certificate rotation schedules. Security teams must implement monitoring solutions that can detect unauthorized certificate installations and VPN service deployments on managed devices. Network segmentation and traffic inspection mechanisms should be strengthened to identify and block suspicious communications that may indicate exploitation of this vulnerability. The affected systems should be configured to enforce certificate pinning for critical security services, preventing the use of unauthorized certificates even if they are installed on the device. Organizations should also conduct comprehensive security audits to identify other potential certificate management weaknesses within their mobile device security infrastructure. Regular security training for device administrators and users should emphasize the importance of certificate security and the risks associated with local privilege escalation. The remediation process should include the implementation of automated certificate management tools that can enforce proper certificate usage policies and detect deviations from established security protocols. Additionally, organizations should establish incident response procedures specifically designed to handle certificate-based security compromises, ensuring that security teams can quickly identify, contain, and remediate exploitation attempts. The vulnerability serves as a critical reminder of the importance of proper cryptographic key management and the dangers of centralized trust mechanisms in security architectures.